KRUGLOV, V. E. Solution of a second-order Poincaré-Perron-type equation and differential equations that can be reduced to it. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 7, p. 900–917, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3208. Acesso em: 5 dec. 2025.